CN111735907B - Method for measuring chloride ion content in industrial lanthanum oxide by potentiometric titration - Google Patents
Method for measuring chloride ion content in industrial lanthanum oxide by potentiometric titration Download PDFInfo
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Abstract
A method for measuring the content of chloride ions in industrial lanthanum oxide by adopting a potentiometric titration method comprises the steps of drying, sample wetting, sample dissolving, interference ion removal, blank calibration, titration of a solution to be measured, titration result calculation and the like. The method expands the detection range of chloride ions in the industrial lanthanum oxide, and effectively improves the detection precision of low-content chloride ions in the industrial lanthanum oxide; the content of chloride ions in the lanthanum oxide is measured by adopting a potentiometric titration method, the measurement precision is high, the operation of the test process is simple, and the detection efficiency can be effectively improved; the invention uses less chemical reagent and has no pollution.
Description
Technical Field
The invention relates to a method for measuring the content of chloride ions in lanthanum oxide, in particular to a method for measuring the content of chloride ions in lanthanum oxide by a potentiometric titration method.
Background
Lanthanum oxide is used as an important rare earth industrial raw material and is widely applied to various photoelectric components. In the production and use, the purity of lanthanum oxide has important influence on the product performance, and the content of chloride ions in impurity components directly influences the formulation of a production process. Therefore, accurate determination of the chloride ion content in lanthanum oxide is of great importance.
At present, the content of chloride ions in industrial lanthanum oxide is measured by mainly adopting a silver nitrate turbidimetric method to calculate the corresponding content of the chloride ions according to the absorbance under a certain wavelength, the method needs to use the relation between the concentration and the absorbance of a series of prepared standard solutions as a working curve, the operation of a test process is complex, the detection period is long, and the detection efficiency is low.
CN109212002A discloses a method for detecting chloride ions in nicotinic acid by an potentiometric titration method, which comprises the steps of weighing a nicotinic acid sample into a beaker, adding deionized water, dissolving in ultrasonic waves, filtering with medium-speed qualitative filter paper into a volumetric flask, and shaking up to constant volume; transferring 50mL of sample liquid from a measuring flask to a beaker, adding 0.5mL of nitric acid solution, placing a rotor and fixing the solution on a magnetic stirrer, adjusting an acidity meter to a potential level, taking a silver electrode as an indicating electrode, taking a double-salt bridge saturated calomel electrode as a reference electrode, and titrating with a silver nitrate standard solution.
CN105092776A discloses a method for determining the content of chlorine in industrial barium sulfate by a full-automatic potentiometric titration method, which comprises the steps of titrating a solution to be determined by a silver nitrate standard solution, judging a titration end point according to the change of potential in the titration process, adding a proper amount of starch into a test solution according to the consumed volume of the silver nitrate solution, and reducing errors caused by dissolution of silver chloride precipitate.
Disclosure of Invention
The invention aims to solve the technical problem of overcoming the defects in the prior art and provides a method for measuring the content of chloride ions in industrial lanthanum oxide by adopting a potentiometric titration method, which has the advantages of high measurement precision, large detection range and high detection efficiency.
The technical scheme adopted by the invention for solving the technical problems is as follows: a method for measuring the content of chloride ions in industrial lanthanum oxide by adopting a potentiometric titration method comprises the following steps:
(1) and (3) drying: burning industrial lanthanum oxide to constant weight, placing the industrial lanthanum oxide in a drying dish, and cooling to room temperature to obtain dry lanthanum oxide;
(2) wetting the sample: uniformly mixing the dry lanthanum oxide, taking part of the dry lanthanum oxide by adopting a shrinkage method, placing the part of the dry lanthanum oxide in a beaker to obtain the industrial lanthanum oxide to be detected, and recording the quality of the industrial lanthanum oxide to be detected asm(ii) a Dropwise adding an ethanol solution into the beaker to fully wet the industrial lanthanum oxide to be detected, covering the surface dish, and cooling to room temperature;
(3) sample dissolution: adding a nitric acid solution into the beaker, enabling the industrial lanthanum oxide to be detected to fully react with the nitric acid solution until the industrial lanthanum oxide and the nitric acid solution are completely dissolved, adding the nitric acid solution again, and cooling to room temperature to obtain a mixed solution;
(4) removing interfering ions: adding an ethylene diamine tetraacetic acid disodium salt solution into the mixed solution, filtering after complete reaction, putting the filtrate into a reaction cup, adding an ethanol solution, and uniformly mixing to obtain a solution to be detected;
(5) blank calibration: preparing a blank standard solution according to the steps (2) to (4) without using lanthanum oxide; adding a sodium chloride standard titration solution, titrating with a silver nitrate standard titration solution under the condition of stirring, and recording a potential value and a corresponding titration volume;
(6) titration of the solution to be tested: adding a sodium chloride standard titration solution with the same concentration as the sodium chloride standard titration solution in the step (5) into the solution to be tested, titrating the solution by using the silver nitrate standard titration solution in the step (5) under the condition of stirring, and recording a potential value and a corresponding titration volume;
(7) and (3) calculating a titration result:
a) titration volume during titration is recordedVThe potential value is recorded as E; according to the relationship between the titration volume and the potential value in the titration process of the silver nitrate standard titration solution, calculating the volume of the silver nitrate standard titration solution consumed by titrating the blank standard titration solution to the end point by adopting a secondary micro-quotient methodV 0And the volume of silver nitrate standard titration solution consumed by titrating the solution to be tested to the end pointV 1；
V 0、V 1The calculation method comprises the following steps:
in the formula:
i =0 or 1; when i =0, each parameter in the formula is a result obtained by blank calibration in the step (5); when i =1, each parameter in the formula is a result obtained by titration of the solution to be detected in the step (6);
V i1——adding the volume of a silver nitrate standard titration solution mL before the potential increment value delta E reaches the maximum value;
V i2the volume of the silver nitrate standard titration solution, mL, added for the last time before the potential increment value delta E reaches the maximum value;
bi——△2E/△2 Vthe last positive value;
B i——△2E/△2 Vthe sum of the absolute values of the last positive value and the first negative value;
b) the content of chloride ions in the industrial lanthanum oxide is calculated by the following method:
in the formula:
c-concentration of silver nitrate standard titration solution, mol/L;
V 1titrating the volume of consumed silver nitrate standard titration solution, mL;
V 0blank calibration of volume of consumed silver nitrate standard titration solution, mL;
m-mass of the titrated sample, g;
35.45-molar mass of Cl, g/mol.
Preferably, in the step (1), the burning temperature is 800-1000 ℃.
Preferably, in the step (2), the mass of the industrial lanthanum oxide to be detected is 1.0000-2.0000 g.
Preferably, in the step (2), the ratio of the ethanol solution to the industrial lanthanum oxide to be measured is 2-3 mL:1 g.
Preferably, in the step (2), the volume concentration of the ethanol solution is 70.0-99.5%.
By dropwise adding a proper amount of ethanol solution to fully wet the lanthanum oxide powder to be detected, chloride ions can be effectively stabilized in the sample dissolving process, the test error is reduced, and the detection precision is improved.
Preferably, in the step (3), the concentration of the nitric acid solution is 30-50 wt%.
Preferably, in the step (3), the ratio of the nitric acid solution added for the first time to the amount of the industrial lanthanum oxide to be measured is 4-6 mL:1 g.
Preferably, in the step (3), the ratio of the nitric acid solution added for the second time to the industrial lanthanum oxide to be detected is 2-3 mL:1g, and the interference of carbonate ions introduced due to moisture absorption of lanthanum oxide is masked by adopting a method of properly adding excessive nitric acid, so that the detection precision is improved.
Preferably, in the step (4), the concentration of the disodium ethylene diamine tetraacetate solution is 0.01-0.05 mol/L.
Preferably, in the step (4), the ratio of the disodium ethylene diamine tetraacetate solution to the industrial lanthanum oxide to be detected is 5-10 mL:1 g.
And a proper amount of ethylene diamine tetraacetic acid disodium salt solution is added, so that the interference of a small amount of metal ions (such as iron ions) in the solution to be detected can be removed, and the detection precision is improved.
Preferably, in the step (4), the volume concentration of the ethanol solution is 70.0-99.5%; the volume of the ethanol solution is 3-4 times of the volume of the filtrate.
Preferably, in the step (5), the concentration of the sodium chloride standard titration solution is 0.01-0.5 mol/L.
Preferably, in the step (5), the volume of the sodium chloride standard titration solution is 2-7% of the volume of the blank standard solution.
Preferably, in the step (5), the concentration of the silver nitrate standard titration solution is 0.01-0.5 mol/L.
In the step (6), a certain known amount of chloride ions are pre-added into the solution to be detected, and a corresponding blank solution titration method is carried out to reduce the blank value of the solution matrix, so that the detection range can be expanded, and the detection precision of low-content chloride ions in the industrial lanthanum oxide is effectively improved. The potentiometric titration method determines the titration end point of the solution by the sudden jump of the electrode potential, has excellent adaptability to the turbid solution to be measured, and has accurate titration end point judgment and high measurement precision.
The invention has the beneficial effects that:
(1) the method expands the detection range of chloride ions in the industrial lanthanum oxide, and effectively improves the detection precision of low-content chloride ions in the industrial lanthanum oxide;
(2) the method adopts a potentiometric titration method to measure the chloride ion content in the lanthanum oxide, determines the titration end point of the solution by a secondary differential quotient calculation method through potential jump, has high measurement precision and simple operation in the test process, and can effectively improve the detection efficiency;
(3) the invention uses less chemical reagent and has no pollution.
Detailed Description
The present invention will be further described with reference to examples and comparative examples.
In each example, the raw materials used were all common commercial products.
Example 1
(1) And (3) drying: burning an industrial lanthanum oxide sample at 800 ℃ for 2h to constant weight, placing the sample in a drying dish, and cooling to room temperature to obtain dry lanthanum oxide;
(2) wetting the sample: uniformly mixing the dry lanthanum oxide, putting 1.0000g of the dry lanthanum oxide into a beaker by adopting a shrinkage method to obtain the industrial lanthanum oxide to be detected, and recording the quality of the industrial lanthanum oxide to be detected asm(ii) a Dropwise adding 3mL of ethanol solution (the volume concentration is 99.5%) to fully wet the industrial lanthanum oxide to be detected, covering a watch glass, and cooling to room temperature;
(3) sample dissolution: slowly adding 5mL of nitric acid solution (with the concentration of 35 wt%) into the beaker, shaking the beaker to enable the industrial lanthanum oxide to be detected to fully react with the nitric acid solution until the industrial lanthanum oxide and the nitric acid solution are completely dissolved, adding 2mL of nitric acid solution (with the concentration of 35 wt%) again, and cooling to room temperature to obtain a mixed solution;
(4) removing interfering ions: adding 10mL of ethylene diamine tetraacetic acid disodium salt solution (the concentration is 0.02 mol/L) into the mixed solution, filtering after the solution completely reacts, putting the filtrate into a reaction cup, adding 60mL of ethanol solution (the volume concentration is 99.5 percent), and uniformly mixing to obtain a solution to be detected;
(5) blank calibration: preparing a blank standard solution according to the steps (2) to (4) without using lanthanum oxide; adding 5mL of sodium chloride standard titration solution (the concentration is 0.1 mol/L), titrating with silver nitrate standard titration solution (the concentration is 0.1 mol/L) under the stirring of a magnetic stirrer, and recording potential values and corresponding titration volumes (see table 1, the potential values are recorded as E);
TABLE 15 mL sodium chloride Standard titration solution potential values and corresponding titration volumes
(6) Titration of the solution to be tested: adding 5mL of sodium chloride standard titration solution (with the concentration of 0.1 mol/L) into the solution to be tested, titrating with silver nitrate standard titration solution (with the concentration of 0.1 mol/L) under the stirring of a magnetic stirrer, and recording potential values and corresponding titration volumes (see table 2, the potential values are recorded as E);
TABLE 2 potential values of the solutions to be tested and the corresponding titration volumes
(7) And (3) calculating a titration result:
a) titration volume during titration is recordedVThe potential value is recorded as E; according to the relationship between the titration volume and the potential value in the titration process of the silver nitrate standard titration solution, calculating the volume of the silver nitrate standard titration solution consumed by titrating the blank standard titration solution to the end point by adopting a secondary micro-quotient methodV 0And the volume of silver nitrate standard titration solution consumed by titrating the solution to be tested to the end pointV 1；
V 0、V 1The calculation method comprises the following steps:
in the formula:
i =0 or 1; when i =0, each parameter in the formula is a result obtained by blank calibration in the step (5); when i =1, each parameter in the formula is a result obtained by titration of the solution to be detected in the step (6);
V i1adding the volume of a silver nitrate standard titration solution mL before the potential increment value delta E reaches the maximum value;
V i2the volume of the silver nitrate standard titration solution, mL, added for the last time before the potential increment value delta E reaches the maximum value;
bi——△2E/△2 Vthe last positive value;
B i——△2E/△2 Vthe sum of the absolute values of the last positive value and the first negative value;
the following calculation results:V 0=：5.0191mL，V 1=：5.1491mL；
b) the content of chloride ions in the industrial lanthanum oxide is calculated by the following method:
in the formula:
c-concentration of silver nitrate standard titration solution, mol/L;
V 1titrating the volume of consumed silver nitrate standard titration solution, mL;
V 0blank calibration of volume of consumed silver nitrate standard titration solution, mL;
m-mass of the titrated sample, g;
35.45-molar mass of Cl, g/mol.
According to calculation, the content of chloride ions in the industrial lanthanum oxide sample is 0.0461%.
In order to demonstrate the accuracy and precision of the method of the present invention, a sample precision test was performed. The chloride ion content of the same industrial lanthanum oxide sample was measured in parallel 6 times according to the above procedure, and the results are shown in Table 3.
TABLE 3 precision test results of inventive example 1
Example 2
(1) And (3) drying: burning an industrial lanthanum oxide sample at 1000 ℃ for 1h to constant weight, placing the sample in a drying dish, and cooling to room temperature to obtain dry lanthanum oxide;
(2) wetting the sample: uniformly mixing the dry lanthanum oxide, putting 2.0000g of the dry lanthanum oxide into a beaker by adopting a shrinkage method to obtain the industrial lanthanum oxide to be detected, and recording the quality of the industrial lanthanum oxide to be detected asm(ii) a Dropwise adding 5mL of ethanol solution (the volume concentration is 99.5%) to fully wet the industrial lanthanum oxide to be detected, covering a watch glass, and cooling to room temperature;
(3) sample dissolution: slowly adding 10mL of nitric acid solution (with the concentration of 35 wt%) into the beaker, shaking the beaker to enable the industrial lanthanum oxide to be detected to fully react with the nitric acid solution until the industrial lanthanum oxide and the nitric acid solution are completely dissolved, adding 5mL of nitric acid solution (with the concentration of 35 wt%) again, and cooling to room temperature to obtain a mixed solution;
(4) removing interfering ions: adding 10mL of ethylene diamine tetraacetic acid disodium salt solution (the concentration is 0.02 mol/L) into the mixed solution, filtering after the solution completely reacts, putting the filtrate into a reaction cup, adding 90mL of ethanol solution (the volume concentration is 99.5%) into the reaction cup, and uniformly mixing to obtain a solution to be detected;
(5) blank calibration: preparing a blank standard solution according to the steps (2) to (4) without using lanthanum oxide; adding 3mL of sodium chloride standard titration solution (the concentration is 0.05 mol/L), titrating with silver nitrate standard titration solution (the concentration is 0.05 mol/L) under the stirring of a magnetic stirrer, and recording a potential value and a corresponding titration volume;
(6) titration of the solution to be tested: adding 3mL of sodium chloride standard titration solution (with the concentration of 0.05 mol/L) into the solution to be tested, titrating with silver nitrate standard titration solution (with the concentration of 0.05 mol/L) under the stirring of a magnetic stirrer, and recording a potential value and a corresponding titration volume;
(7) and (3) calculating a titration result:
a) titration volume during titration is recordedVThe potential value is recorded as E; according to the relationship between the titration volume and the potential value in the titration process of the silver nitrate standard titration solution, calculating the volume of the silver nitrate standard titration solution consumed by titrating the blank standard titration solution to the end point by adopting a secondary micro-quotient methodV 0And the volume of silver nitrate standard titration solution consumed by titrating the solution to be tested to the end pointV 1；
The calculation method is the same as that of the embodiment 1, and the following results are obtained through calculation:V 0=：3.0015mL，V 1=：3.0386mL；
b) the content of chloride ions in the industrial lanthanum oxide is calculated, the calculation method is the same as that in the example 1, and the content of the chloride ions in the industrial lanthanum oxide sample is calculated to be 0.0132%.
Comparative example
Taking the industrial lanthanum oxide used in the embodiment 1 as a sample to be tested, and parallelly determining the chloride ion content of the industrial lanthanum oxide 6 times by using a silver nitrate turbidimetric method, wherein the operation steps are as follows:
(1) burning an industrial lanthanum oxide sample at 900 ℃ for 1h, and cooling to room temperature in a dryer;
(2) weighing 1.000g of sample in a 150mL conical flask, adding 20mL of nitric acid solution (with the concentration of 25 wt%) to dissolve the sample, heating at low temperature to dissolve the sample until the sample is clear, and adding pure water in a 50mL volumetric flask to fix the volume;
(3) dividing two 5mL test solutions from the solution with constant volume into 25mL colorimetric tubes, adding 1mL nitric acid solution (with the concentration of 50 wt%) and 2mL glycerol solution (with the volume percentage of 50%) step by step, and gently mixing; diluting one part of the solution with water to a scale, and lightly mixing the diluted solution to serve as a compensation solution; adding 2mL of silver nitrate (the concentration is 5 g/L) into the other part, slightly mixing the mixture, diluting the mixture to a scale with water, and slightly mixing the mixture; placing the two colorimetric tubes into a water bath at 60 ℃ for heat preservation for 15min, and cooling to room temperature to obtain a solution to be detected;
(4) weighing 1.6485g of sodium chloride (guaranteed reagent) burned at 400 ℃ in a 500mL beaker, adding 200mL of pure water for dissolving, and fixing the volume in a 1000mL volumetric flask by using the pure water to prepare a chlorine standard storage solution with the concentration of 1 mg/mL; transferring 10.00mL of chlorine standard storage solution into a 500mL volumetric flask, diluting the solution to a scale with pure water, and uniformly mixing the solution to prepare a chlorine standard solution with the concentration of 20 mu g/mL; respectively transferring 0mL, 1.00mL, 2.00mL, 3.00mL and 4.00mL from 20 mu g/mL chlorine standard solution into 5 colorimetric tubes with 25mL, respectively adding 2.0mL of nitric acid (the concentration is 50 wt%), adding silver nitrate according to the step (3), adding water for diluting to a scale, uniformly mixing, carrying out water bath heat preservation, and cooling to room temperature; drawing a working curve by taking the chlorine concentration as an abscissa and the absorbance as an ordinate;
(5) preparing a blank sample according to the steps (2) to (3) without using lanthanum oxide; transferring the blank sample into a 3cm absorption cell, using water as a reference, and measuring the absorbance of the blank sample at the wavelength of 430nm of a spectrophotometer;
(6) transferring the solution to be measured into a 3cm absorption cell, using a compensation solution as a reference, and measuring the absorbance of the solution at the wavelength of 430nm of a spectrophotometer; finding out the chlorine amount in the solution to be detected from the working curve;
calculating the mass fraction of chlorine in the industrial lanthanum oxide according to the formula (3):
in the formula:
m 1-finding out the chlorine content, μ g, of the solution to be tested on the curve;
V 0-total volume of solution to be tested, mL;
V 1-removing the volume, mL, of the solution to be tested;
m 0-mass of the sample to be tested, g;
comparative example test results are shown in table 4. The standard deviation and relative standard deviation of the comparative examples are significantly higher than those of example 1.
Table 4 precision test results of comparative examples
Claims (7)
1. A method for measuring the content of chloride ions in industrial lanthanum oxide by adopting a potentiometric titration method is characterized by comprising the following steps:
(1) and (3) drying: burning industrial lanthanum oxide to constant weight, placing the industrial lanthanum oxide in a drying dish, and cooling to room temperature to obtain dry lanthanum oxide;
(2) wetting the sample: uniformly mixing the dry lanthanum oxide, taking part of the dry lanthanum oxide by adopting a shrinkage method, placing the part of the dry lanthanum oxide in a beaker to obtain the industrial lanthanum oxide to be detected, and recording the quality of the industrial lanthanum oxide to be detected asm(ii) a Dropwise adding an ethanol solution into the beaker to fully wet the industrial lanthanum oxide to be detected, covering the surface dish, and cooling to room temperature; the dosage ratio of the ethanol solution to the industrial lanthanum oxide to be detected is 2-3 mL:1 g; the volume concentration of the ethanol solution is 70.0-99.5%;
(3) sample dissolution: adding a nitric acid solution into the beaker, enabling the industrial lanthanum oxide to be detected to fully react with the nitric acid solution until the industrial lanthanum oxide and the nitric acid solution are completely dissolved, adding the nitric acid solution again, and cooling to room temperature to obtain a mixed solution;
(4) removing interfering ions: adding an ethylene diamine tetraacetic acid disodium salt solution into the mixed solution, filtering after complete reaction, putting the filtrate into a reaction cup, adding an ethanol solution, and uniformly mixing to obtain a solution to be detected;
(5) blank calibration: preparing a blank standard solution according to the steps (2) to (4) without using lanthanum oxide; adding a sodium chloride standard titration solution, titrating with a silver nitrate standard titration solution under the condition of stirring, and recording a potential value and a corresponding titration volume;
(6) titration of the solution to be tested: adding a sodium chloride standard titration solution with the same concentration as the sodium chloride standard titration solution in the step (5) into the solution to be tested, titrating the solution by using the silver nitrate standard titration solution in the step (5) under the condition of stirring, and recording a potential value and a corresponding titration volume;
(7) and (3) calculating a titration result:
a) titration volume during titration is recordedVThe potential value is recorded as E; according to the relationship between the titration volume and the potential value in the titration process of the silver nitrate standard titration solution, calculating the volume of the silver nitrate standard titration solution consumed by titrating the blank standard titration solution to the end point by adopting a secondary micro-quotient methodV 0And the volume of silver nitrate standard titration solution consumed by titrating the solution to be tested to the end pointV 1；
V 0、V 1The calculation method comprises the following steps:
in the formula:
i =0 or 1; when i =0, each parameter in the formula is a result obtained by blank calibration in the step (5); when i =1, each parameter in the formula is a result obtained by titration of the solution to be detected in the step (6);
V i1adding the volume of a silver nitrate standard titration solution mL before the potential increment value delta E reaches the maximum value;
V i2the volume of the silver nitrate standard titration solution, mL, added for the last time before the potential increment value delta E reaches the maximum value;
bi——△2E/△2 Vthe last positive value;
B i——△2E/△2 Vthe sum of the absolute values of the last positive value and the first negative value;
b) the content of chloride ions in the industrial lanthanum oxide is calculated by the following method:
in the formula:
c-silver nitrate markThe concentration of the quasi-titration solution, mol/L;
V 1titrating the volume of consumed silver nitrate standard titration solution, mL;
V 0blank calibration of volume of consumed silver nitrate standard titration solution, mL;
m-mass of the titrated sample, g;
35.45-molar mass of Cl, g/mol.
2. The method for measuring the chloride ion content in the industrial lanthanum oxide by adopting the potentiometric titration method as claimed in claim 1, wherein the burning temperature in the step (1) is 800-1000 ℃.
3. The method for determining the chloride ion content in the industrial lanthanum oxide by adopting the potentiometric titration method as claimed in claim 1 or 2, wherein in the step (2), the mass of the industrial lanthanum oxide to be determined is 1.0000-2.0000 g.
4. The method for measuring the chloride ion content in the industrial lanthanum oxide by adopting the potentiometric titration method according to claim 1 or 2, wherein in the step (3), the concentration of the nitric acid solution is 30-50 wt%; the ratio of the amount of the nitric acid solution added for the first time to the amount of the industrial lanthanum oxide to be detected is 4-6 mL:1 g; the ratio of the nitric acid solution added for the second time to the amount of the industrial lanthanum oxide to be detected is 2-3 mL:1 g.
5. The method for measuring the chloride ion content in the industrial lanthanum oxide by adopting the potentiometric titration method as claimed in claim 1 or 2, wherein in the step (4), the concentration of the disodium ethylene diamine tetraacetate solution is 0.01-0.05 mol/L; the dosage ratio of the ethylene diamine tetraacetic acid disodium salt solution to the industrial lanthanum oxide to be detected is 5-10 mL:1 g.
6. The method for measuring the content of chloride ions in the industrial lanthanum oxide by adopting the potentiometric titration method according to claim 1 or 2, wherein in the step (4), the volume concentration of the ethanol solution is 70.0-99.5%; the volume of the ethanol solution is 3-4 times of the volume of the filtrate.
7. The method for measuring the content of chloride ions in the industrial lanthanum oxide by adopting the potentiometric titration method according to claim 1 or 2, wherein in the step (5), the concentration of the sodium chloride standard titration solution is 0.01-0.5 mol/L; the volume of the sodium chloride standard titration solution is 2-7% of the volume of the blank standard solution; the concentration of the silver nitrate standard titration solution is 0.01-0.5 mol/L.
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| CN112816615B (en) * | 2021-01-07 | 2023-06-20 | 沈阳力创环保科技有限公司 | Chloride ion detector and chloride ion detection method |
| CN114384199B (en) * | 2022-01-17 | 2022-11-01 | 杭州沐源生物医药科技有限公司 | Method for determining content of potassium chloride particles by potentiometric titration |
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